iodine124

Iodine-124 is a radioactive isotope of iodine with a mass number of 124 and an atomic number of 53. It has a half-life of about 4.18 days and decays by positron emission and electron capture to tellurium-124. The decay is accompanied by the emission of prompt gamma rays, which makes the isotope useful for imaging as well as for spectroscopic studies.

Production and chemical behavior

I-124 is typically produced in cyclotrons by irradiating tellurium-124 targets with protons via the Te-124(p,n)I-124 reaction. The resulting radionuclide exists as iodide, allowing it to participate in standard iodination chemistry and to be incorporated into radiopharmaceuticals for imaging or research purposes. Its chemical similarity to stable iodine enables convenient labeling of a wide range of iodine-containing compounds and biomolecules.

Applications in imaging and research

Due to its relatively long half-life and positron emission, iodine-124 is widely used for positron emission tomography (PET) imaging, especially in applications requiring longer observation times or the tracking of iodine-labeled biologics, antibodies, and small molecules. It also provides high-energy gamma photons that can be detected by gamma cameras, enabling complementary imaging and dosimetry studies. I-124 is valuable for thyroid physiology investigations, pre-therapy planning for radioiodine treatments, and the development and validation of iodine-based radiopharmaceuticals.

Safety and handling

Iodine-124 emits beta and gamma radiation, requiring appropriate radiological containment, monitoring, and disposal in accordance with regulatory standards. Handling protocols emphasize minimizing exposure and ensuring proper waste management given its 4-day-scale half-life and medical research applications.